Thermoplastic pipes and valves are employed in a broad range of chemical or chemical engineering systems. Thermal plastic valves and pipes are particularly desirable for systems handling highly corrosive fluids such as acids and other oxidizing chemicals, caustics, solvents and halogens. These corrosive chemicals frequently flow at high temperatures and high pressures (e.g. 150 PSI, 250.degree. F.).
The chemical engineering or chemical processes carried out in these complex systems of thermoplastic valves and pipes invariably depend upon the accurate and timely on and off sequencing of valves throughout the system. For example, it may be necessary to shut off or turn on several lines of a system at the same time. Alternatively, it may be necessary to completely stop fluid flow in one line while simultaneously initiating flow in a different line. An incorrect or incomplete sequencing of such valve operations can have a substantial costly and occasionally hazardous effect.
Ball valves and butterfly valves often are used to carry out this on and off sequencing of fluid flows. Valves of this type typically are positioned to be in either a complete open position or a completely closed position. More particularly, ball valves include a sphere rotationally mounted in the fluid flow path of the valve. The sphere or ball includes a cylindrical passage extending entirely therethrough. This cylindrical passage is aligned such that fluid flow through the valve is substantially umimpeded in one rotational position of the ball, while a 90.degree. rotation of the ball causes a complete blockage of the fluid flow path. Similarly, butterfly valves include a generally circular disc rotationally mounted in the fluid flow path. In one rotational position, the disc permits a substantially unimpeded fluid flow through the valve, while a 90.degree. rotation of the disc completely blocks the fluid flow.
Manually operated valves are quite acceptable in systems having a relatively small number of valves or in systems where the precise sequencing of valve operations is not critical. However, many chemical engineering and chemica systems are extremely complex and include a large number of valves, the precise sequencing of which is very critical. Therefore, many such systems utilize arrays of motor operated valves. These automated valves typically include an electric or pneumatic motor in communication with the valve stem and adapted to rotate the valve stem through substantially precisely 90.degree. of rotation. One such electrically operated valve is shown and described in a copending application entitled MOTOR OPERATED VALVE by H. Peter van Lingen, Ser. No. 671,485 filed 11-11-84, now U.S. Pat. No. 4,556,194, issued 12-3-84, of which is incorporated herein by reference.
Although the above described automated valves generally can be quite efficient, they also tend to be costly. The cost of such valves can become significant in complex systems requiring many such valves.
In view of the above it is an object of the subject invention to provide an assembly for efficiently operating a plurality of valves in a fluid flow system.
It is an additional object of the subject invention to provide an assembly wherein the operation of one valve can cause the simultaneous operation of at least one other valve.
It is still another object of the subject invention to provide an assembly including a motor for simultaneously operating a plurality of valves.